How do groups of animals make collective decisions? Last week, we learned that bees reach consensus by headbutting those with opposing views. But in many other species, the decision-making process is a bit more democratic. In cases where social animals are unrelated and have different self-interests (such as our own), contrasting opinions are common. But it can be just as common for individuals to either be uninformed about the options, or simply not care much about the decision.

Researchers have long wondered how the dynamics of decision-making work in these cases. Some evidence suggests that those who are ignorant or naïve are subject to manipulation by a loud, opinionated minority. If this is true, uninformed individuals are detrimental to democratic decision-making, since they can turn over power to a minority. However, a new study in this week’s Science shows that, under certain conditions, uninformed individuals actually shift the balance toward the majority, enabling a democratic process where the majority rules. Continue reading »

A remote colony of birds kept flying away before anyone could count them, so a team of ecologists built a do-it-yourself aerial drone to spy on them from above.

The team made their drone out of a 4.6-foot-wide radio-controlled airplane, two cameras and a GPS tracking unit, all for less than $2,000.

It was the first time scientists have used an unmanned aerial vehicle to inventory a remote bird population, said ecologist and project leader Francesc Sardà-Palomera of Centre Tecnològic Forestal de Catalunya Solsona in Catalonia, Spain.

Abstract

The “Monty Hall Dilemma” (MHD) is a well known probability puzzle in which a player tries to guess which of three doors conceals a desirable prize. After an initial choice is made, one of the remaining doors is opened, revealing no prize. The player is then given the option of staying with their initial guess or switching to the other unopened door. Most people opt to stay with their initial guess, despite the fact that switching doubles the probability of winning. A series of experiments investigated whether pigeons (Columba livia), like most humans, would fail to maximize their expected winnings in a version of the MHD. Birds completed multiple trials of a standard MHD, with the three response keys in an operant chamber serving as the three doors and access to mixed grain as the prize. Across experiments, the probability of gaining reinforcement for switching and staying was manipulated, and birds adjusted their probability of switching and staying to approximate the optimal strategy. Replication of the procedure with human participants showed that humans failed to adopt optimal strategies, even with extensive training.

It seems obvious: Stripes conceal a tiger in the tall grass, whereas spots help a jaguar remain hidden in its shadowy rainforest home. But is this true? Using Internet image searches and wildlife photo archives, researchers classified 35 species of cats according to their markings, including the size, shape, and direction of the pattern. Then the researchers compared those characteristics with factors such as habitat, prey size, and hunting time. As the team reports online today in the Proceedings of the Royal Society B, in each case, the cat’s markings provided camouflage specific to its habitat, confirming the common wisdom. Spotted cats frequent forests, striped tigers lurk in tall grass, and unmarked lions range out in the open. The team also found that the most irregularly marked species, including jaguars and leopards, tend to hunt at night, where their patterns can confuse the night vision of their prey. All of which suggests that protecting big cats means protecting their habitats as well.